How Often to Change Spark Plugs

How Often to Change Spark Plugs – Spark plugs are the components responsible for burning the fuel when it is inside the combustion chambers. Its spark starts the explosion that drives the pistons, moving the engine continuously. But the sails have a lifespan and should be inspected by the mechanic every 10,000 km in most national vehicles.

How Often to Change Spark Plugs

Just like the smoke emitted by the exhaust, inspecting the spark plugs periodically can give us a lot of information about the overall state of the engine because depending on the state, the spark plugs indicate defects that could compromise other components and prevent more significant damage from happening.

 

Ignition Candles – Defects and Symptoms

After 10.ooo km rotated, you can already see various symptoms and problems indicated by the state of the sails. Let’s describe the main and most common ones to identify after removing the candle set. Are they:

Natural wear

If the insulation foot is slightly yellowish or brown, it indicates that everything went well during the life of the candles. The engine is in good condition and the type of the spark plug was correct for this engine.

Excessive natural wear

Even if the engine is in good condition and the spark plugs are correct for the engine type, remaining too long without replacing the spark plugs will cause excessive wear of the central electrode (erosion). The distance between the electrodes becomes very large and the high voltage supplied by the coil (s) becomes insufficient to cause the spark.

Symptoms:
– Engine bumps, especially when accelerating for overtaking or overhangs.
“Starting the engine is more difficult.” It takes time to get it.

Corrosion of electrodes

This situation is usually confused with electrode melting due to overheating. Contrary to what it seems, this symptom is caused by the presence of corrosive agents and/or additives in the fuel or lubricating oil and it is common to find deposits of waste that end up influencing the flow of gases. It is also usually caused by poor fuel.

Symptoms:
– Engine bumps, especially when accelerating for overtaking or overhangs.
“Starting the engine is more difficult.” It takes time to get it.

Black soot (dry carbonization)

The formation of this black and dry soot, covering the electrodes and the candle head, can have several causes. The main ones are: Dirty air filter, choked or malfunctioning choke, poor fuel, carburetor or injection deregulated (air-fuel mixture very rich), engine running at low speed for a long time, point adjustment very late ignition (delayed spark), use of inadequate (too cold) candles.

Symptoms:
– Difficulty starting the engine, especially when it is still cold.
– Engine fails when in idle speed.

In cases where you have filled up with poor gasoline, having the vehicle run in first or second gear, with high speed for a few moments you can eliminate the impurities accumulated at the end of the sail if the car is already supplied with quality fuel. Even so, it is important to check the regulation and the filters. Replacing candles with new ones is also a good idea.

Black and oily soil (oily carbonization)

This indicates serious problems with the motor head and possibly a grinding service will be required. The electrodes are covered with a layer of oil and charcoal, which indicates excess engine oil passing into the combustion chamber due to wear or defect in the piston rings and/or valve guides.

Symptoms:
– Difficulty starting the engine, especially when it is still cold.
– Engine fails when in idle speed.

Waste of Lead

Yellowish spots, especially around the insulator, indicate a lot of lead concentration in the fuel which should NOT be of good quality precisely because of this. As the temperature in the combustion chamber increases, these debris tends to become electric conductors by canceling out the candle’s functionality and causing ignition (ie sparking) faults. In this case, it is no use trying to clean the candles, since the lead must have already glazed over the ceramic of the insulator. Changing the station where you fuel should also help.

Symptoms:
– Ignition spark faults, especially at higher speeds.

Other Residues and Impurities

Oil and/or fuel additives may leave “incombustible” (non-burnt) wastes in the combustion chamber. This debris can be visible on the pistons, valves, head and the candle itself. It occurs especially in engines with oil consumption above normal or fueled with poor fuel. Cleaning and proper engine adjustment may solve the problem.

Symptoms:
– Loss of engine power.
– Damage to engine and cylinder head.

Overheating

There are several reasons that may cause melting of the central electrode, partially melting. The most common are: the use of incorrect (too hot) candles, debris (dirt) in the combustion chamber, faulty valves, deregulated ignition (front), poor fuel-air mixture, defective dispenser, poor fuel or candles poorly installed / tight.

Symptoms:
– Loss of engine power.
– Ignition spark faults.
– Damn the engine.

Cast Central Electrode

The melting of the central electrode can be aggravated by the overheating of the combustion chamber, causing cracks and breaks in the insulation foot. The causes are still the same but the damage to the engine may already be greater. In this case, it will be necessary to check the engine and ignition and power systems.

Symptoms:
– Loss of engine power.
– Ignition spark faults.
– Damn the engine.

Central and Lateral Cast Electrodes

At this point, the combustion takes place by incandescence, that is, there is no more spark and the high temperature causes the fuel to burn. Continued use of improper candles and fuels can cause the spark plugs to reach this state.

If the engine has not yet broken at this point, you should still be noticing symptoms such as:
– Engine power loss.
– Ignition spark faults.
– Damn the engine.

Cracked or broken insulation

Aggressive additives added to the fuel can cause corrosion of the central electrode and, over time, cracking the insulator, as well as a lot of combustion soot accumulated between the insulator and the central electrode.

It is also very common that this damage is caused by the use of improper tools in candle maintenance, for example using a screwdriver to push away the electrodes. With the broken insulator the spark jumps from the central electrode directly to the side shell of the candle.

Symptoms:
– Difficulty in starting the engine.
– Ignition faults.

 

IMPORTANT:

Note that you may notice the same symptoms being caused by different defects. Therefore, it is important that your reliable mechanic give your opinion on what may be causing these problems.
In any of these situations, take the time to replace the set of candles in your car with new spark plugs, verifying the correct application described on the package.
Never reuse damaged spark plugs. Cleaning, sanding, or approaching the electrodes will not return their functionality correctly. Remember that there are specific tools for removing and installing the spark plugs and the tightening torque varies from one model to another. So if you do not have the right equipment, let your mechanic do this for you.

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